Aircraft instrument panel

ABSTRACT

The invention relates to aircraft instrument panel equipment. According to the invention, the proposal is for an instrument panel which, in addition to a main display system for horizon and necessary piloting parameters, comprises two items of equipment identical from the point of view of hardware and the point of view of software, each provided with a display screen, automatic pilot set point adjustment buttons, computing means and standby data (standby horizon, altitude, speed). In normal operating conditions, one of the items of equipment is configured in an “automatic pilot set point display” mode; its control buttons are used to give the set points to the automatic pilot computer, and the set points are displayed on the screen. The other item of equipment is configured in “integrated standby data display” mode. It displays on the screen the standby horizon, the standby speed and the standby altitude. The mode may be switched at will or in the event of a failure of one of the two items of equipment.

The invention relates to instruments for aiding the piloting ofaircraft. More precisely, it relates to the instruments on boardaircraft whose piloting requires, for technical reasons or forregulatory reasons, the presence of standby instruments to displayessential navigation data in the event that the main display systemsfail.

In a typical example, for a commercial aircraft transporting passengers,the aircraft instrument panel comprises amongst other things:

-   -   a main display for displaying with great precision a horizon, an        attitude of the aircraft, and altitude, heading and speed data;        this display receives the information computed by a computer of        the airplane based on data received from various sensors;    -   a standby horizon, a standby altimeter, and a standby anemometer        independent of the main system, for displaying in a more concise        manner and with less precision a horizon, an altitude, a speed        and where necessary some other data; the displayed information        is computed by these independent instruments themselves, the        latter receiving signals from sensors less sophisticated than        those that are used for the main display; the standby horizon,        the standby altimeter and the standby anemometer may be grouped        together in an “integrated electronics standby instrument” which        displays all the standby information on one and the same color        screen. The sensors associated with the integrated electronics        standby instrument may or may not be integrated into this        instrument; if the primary display system fails, the pilot uses        the data from the standby instruments.

The main display system is duplicated when the cockpit comprises a pilotstation and a copilot station. The primary displays are duplicated butthe standby instrument is not usually duplicated. It is placed on thepilot side.

Furthermore, aircraft intended to fly long distances may also have anautomatic pilot system, and the instrument panel then comprises an itemof equipment for automatic pilot control. This item of equipmentcomprises manual control buttons that the pilot actuates to set adesired heading, a desired altitude, a desired speed, and a desiredclimb or descent gradient (or instead of a desired gradient, a desiredvertical climb or descent speed, which amounts to the same thing). Thecontrol buttons are used to actuate angle coders whose logic signals areprocessed in the control station to allow the generation of controlsignals representing the set points chosen by the pilot. These signalsare sent to the automatic pilot computer which controls the trajectoryof the aircraft. At the same time, these control signals are used in thecontrol station itself to display therein, for the attention of thepilot or pilots, the set point values chosen manually by means of thecontrol buttons.

Finally, in large sized commercial airplanes, for safety reasons,provision is made for all the electronics and the software for operatingthe automatic pilot computer to be duplicated; thus, if a failure occursin one hardware or software element of a computing channel, the otherchannel can take over. The computer therefore comprises two computingchannels (including two channels in the electronic elements of theautomatic pilot control panel on the instrument panel), and a check ofone of the channels by the other to constantly verify that there is nodivergence in the processing carried out by the two channels.

The whole instrument panel is particularly costly when all theabovementioned requirements or even simply some of them must besatisfied. One aim of the invention is to make the instrument panel lesscostly.

According to the invention, the proposal is for an instrument panelwhich, in addition to a main display system for horizon and necessarypiloting parameters, comprises two items of equipment identical from thepoint of view of hardware and the point of view of software, which areeach provided with a display screen, automatic pilot control means(particularly buttons for adjusting set points given by the pilot),computing means and standby data (standby horizon, standby altitude,standby speed in principle) and means of displaying these data on thedisplay screen.

In normal operating conditions, one of the items of equipment isconfigured in an “automatic pilot set point display” mode; its controlbuttons are then used to give the set points to the automatic pilotcomputer, and the set points are displayed on the screen. The other itemof equipment is configured in “integrated standby data display” mode. Itdisplays on the screen the standby horizon, the standby speed and thestandby altitude which it computes based on signals supplied by sensors;the sensors, preferably, are not part of the equipment; they are outsidethe equipment and they supply their measurement signals simultaneouslyto the two items of equipment.

Since the items of equipment are identical, the production cost islower. Furthermore, since the two items of equipment are identical, theycan be used to satisfy the requirement for the presence of a dualcomputing channel for the automatic pilot. The equipment that displaysthe standby data has the computing software used for the “automaticpilot set point display” mode and this software runs, but withoutdisplaying the automatic pilot set points, even when the equipment is in“standby data display” mode. It receives the set points from the otheritem of equipment and processes them in order to send them independentlyof the other item of equipment to the automatic pilot computer.

In operating conditions in which one of the two items of equipment hasfailed, the other automatically configures itself in “automatic pilotset point display” mode. As a variant, since the two items of equipmenthave all that is necessary to display the standby data, the item ofequipment that has not failed may display the automatic pilot data onone half of the screen and the standby data on the other. This is adegraded display mode, but is acceptable because it would be used onlyin case of failure.

Finally, in the event of dual piloting, with a pilot and a copilot, thedisplay systems being placed between the pilot and the copilot,provision is preferably made for a switchover control button to bepresent on each of the items of equipment to invert the working modes ofthe two items of equipment depending on the person who has the helm: thepilot on the left will in principle require the equipment closest to himto be in piloting set point display mode and the equipment furthest fromhim to be in standby data display mode. When the copilot on the righttakes the helm, he inverts the modes in order to require the equipmentclosest to him to be in automatic pilot set point display mode.

In summary, the invention proposes an aircraft instrument panelcomprising on the one hand at least one main display system for horizonand necessary piloting parameters, and on the other hand an item ofautomatic pilot control equipment, which comprises manual piloting setpoint control buttons and finally an item of standby display equipmentallowing the display, independently of the main display system, ofintegrated standby data including a standby horizon, characterized inthat the automatic pilot control equipment and the standby displayequipment are two identical items of equipment from the hardware pointof view and the software point of view and each comprises a displayscreen capable of displaying the integrated standby data, and in thatthe two items of equipment have at least two operating modes, one of themodes being an integrated standby data display mode and the other beinga mode of displaying the automatic pilot set points given by the pilot,the items of equipment each operating in a different mode in normaloperating conditions.

The set points given by the pilot are entered via control buttons on theequipment that is in set point display mode. Preferably, these setpoints are sent at the same time to the two items of equipment, whichprocess them in parallel to send the corresponding instructions, via twoindependent channels, to two independent computing systems of anautomatic pilot computer with redundant computing channels.

The invention relates not only to an instrument panel thus constituted,but also to the integrated standby equipment itself, suitable for beinginstalled on this instrument panel, the integrated standby equipmentcomprising both the hardware and the software capable of displaying on asingle display screen either the standby data, including a standbyhorizon, when the equipment is operating in a standby data display mode,or automatic pilot set points when the equipment is operating in apiloting set point display mode, the equipment being provided with setpoint adjustment buttons.

Other features and advantages of the invention will appear on readingthe following detailed description made with reference to the appendeddrawings in which:

FIG. 1 represents an integrated standby instrument of the prior art;

FIG. 2 represents an automatic pilot control panel of the prior art;

FIG. 3 represents an instrument panel combining the elements of FIGS. 1and 2;

FIG. 4 represents an instrument panel according to the invention;

FIG. 5 represents in greater detail a possible configuration of the twoidentical items of equipment of the invention, when they are operatingone in an automatic pilot set point display mode and the other in astandby data display mode.

FIG. 1 shows an integrated electronics standby instrument 10, whichcomprises a color screen 12 for the display of a horizon 14 (ground inbrown below, sky in blue above) and standby data necessary for piloting,that is mainly altitude (scrolling graduated scale 16 on the right),speed (scrolling graduated scale 18 on the left), and an airplaneattitude symbol 20. The horizon and data are displayed according to acomputation made by the instrument based on signals originating fromsensors some of which are outside the instrument and others of which maybe inside or outside the instrument. The sensors are usually pressuresensors (for the speed and for the altitude) and an inertia measurementunit for the attitude.

The instrument usually comprises an adjustment button 22 used to resetthe atmospheric pressure according to data communicated locally (forexample supplied by the weather services close to an airport). Itcomprises other control buttons 24 serving various purposes (resettingthe horizon, placing marks on the screen for authorized speed oraltitude ranges, etc.). The instrument comprises electronic circuits andonboard software. It supplies information independent of that which isgiven by the main aircraft navigation aid systems.

FIG. 2 represents an automatic pilot control station 30. It essentiallycomprises buttons for adjusting set point values given by the pilot toan automatic pilot computer present in the aircraft. And it comprisessmall screens for displaying the set point values entered, so that thepilot can check the action he takes on the buttons. For example, thereare four set point buttons 32, 34, 36, 38 respectively for the aircraftspeed, the heading and the track, the altitude and the climb or descentgradient (pitch). And there are four corresponding displays 33, 35, 37,39, each beside the corresponding set point button.

The other control buttons of the automatic pilot control panel, numberedfor example 40, 42, are automatic pilot engagement or disengagementbuttons, piloting mode selection buttons, etc.

FIG. 3 represents a passenger transport airplane instrument panel, withpilot station and copilot station. The main display system comprisesseveral piloting and navigation screens. For piloting, the horizon andpiloting data are displayed on a screen 50 for the pilot and a screen 60for the copilot. Other screens 52, 54, for the pilot, 62, 64 for thecopilot, and 70, 72 (for the pilot and copilot combined) supply otherindications useful for piloting or navigation. The integratedelectronics standby instrument 10 is placed on the pilot side. Theautomatic pilot control panel 30 alone is placed above the array ofpiloting and navigation display systems. The pilot and copilot haveaccess to the automatic pilot control panel which is in the center ofthe instrument panel in the upper portion of the latter. The automaticpilot set points are handled as has been said on two independentcomputing channels but based on a single control panel.

FIG. 4 represents an example of an instrument panel according to theinvention. The main display systems, for piloting as for navigation areconventional and may be identical to those of FIG. 3: screens 50, 52,54, 60, 62, 64, 70, 72. The integrated electronics standby instrument isnow placed beside the automatic pilot control panel, above these maindisplay systems. And the standby instrument and the automatic pilotcontrol panel now consist of two identical and interchangeable items ofequipment, both from the hardware point of view and the software pointof view, and they are coupled together to be able to operate together ina consistent manner. These two items of equipment, side by side, areindicated here by reference numbers 80 and 80′.

In normal operating mode of the aircraft (no failure of the aircraft'smain display system, and no failure of one or other of the items ofequipment 80 and 80′), each item of equipment may perform both of thetypes of tasks for which it is designed: tasks of computing standby dataon the one hand to play the role of integrated electronics standbyinstrument and tasks of automatic piloting to play the role of automaticpilot control panel; but, with respect to the display on theirrespective screen, they operate at a given moment in two different modesand not in one and the same mode: one displays the computed standby databut does not display the automatic pilot set point indications; theother does not display the standby data but displays indicationsspecific to the automatic pilot and in particular the set points thatare given by the pilot or copilot.

A switchover control button 81, 81′ on each of the items of equipment 80and 80′ is used to switch the operating mode of the items of equipmentto invert the roles. The equipment that was in the “standby datadisplay” mode switches to the “automatic pilot set point display” mode,and vice-versa, at the command of the button for changing the mode ofone or other of the items of equipment. This switchover is in practicecarried out during a transition from piloting by the pilot (left seat ofthe airplane) to a piloting by the copilot (right seat), so that theperson piloting has on his side the automatic pilot data display (innormal operating conditions with no failure). The mode switchover buttonof one of the items of equipment therefore acts on the one hand toinvert the mode of that item of equipment and on the other hand to senda mode inversion signal to the other identical item of equipment.

The action on the set point control buttons of the equipment that is inpiloting set point display mode (for example equipment 80) causes thisitem of equipment to compute data for sending to the airplane automaticpilot computer, but also to display the set point data required by thisaction. And, simultaneously, the signals originating from the controlbuttons of this item of equipment are transmitted to the other item ofequipment (80′), which generates in the same manner signals for sendingto the automatic pilot computer. The signals originating from the itemof equipment 80 and 80′, for sending to the computer, may therefore begenerated independently (irrespective of the action on the controlbuttons which is a unique action) and transmitted to two independentchannels of the automatic pilot computer. This makes it possible tosatisfy an automatic pilot safety requirement, in the form of anindependent processing by two distinct items of equipment when the twoitems of equipment display different information intended for thepilots.

If the main display systems fail, the pilot has the choice, via thedisplay switchover control button, of placing close to him the standbydata display or of keeping close to him the automatic pilot controldisplay. In the landing approach phase, he will place the standby datadisplay close to him.

In the event of failure of one of the two items of equipment 80 and 80′,the equipment that is still operating will, as a matter of course, beplaced in automatic pilot set point display mode, if it is not alreadyin that mode, so that the pilot retains control of the piloting mode andthat of the set points that he gives.

It is assumed that the main display systems and an item of equipment 80and 80′ are not simultaneously failed, in which case the standby datawould be lost. However, even in this case, the pilot may, in the landingphase and after selecting manual pilot mode, switch back the item ofequipment 80 or 80′ that has not failed to the standby data displaymode.

As a variant, if an item of equipment 80 or 80′ fails, provision can bemade for the item of equipment that has not failed to switch to a thirddisplay mode, which is a degraded mode, in which one portion of thescreen displays the standby data and another portion displays theautomatic pilot data.

FIG. 5 represents side by side the two items of equipment 80 and 80′according to the invention, in normal operating conditions, that is tosay one displaying the automatic pilot data and the other displaying thestandby data and in particular the standby horizon.

The screen of the item of equipment 80 displays the same indications asthe integrated electronics standby instrument 10 of FIG. 1. The screenof the item of equipment 80′ displays in particular the automatic pilotset points given by the pilot. These set points are displayed in a formdifferent from that of the prior art since there are no longer any smallindividual displays placed beside each set point adjustment button aswas the case for example in FIG. 2. The set points are now displayed ona large screen which can for example be divided (in piloting set pointdisplay mode) into four zones 102, 104, 106, 108, corresponding to fourdifferent set points. Each zone is close to a respective set pointadjustment button 103, 105, 107, 109.

Amongst the control buttons of the item of equipment 80 or 80′, thereare therefore at least four piloting set point control buttons,respectively for the speed (top left), the heading (bottom left), thealtitude (top right) and the vertical speed (bottom right). There isalso a rotating adjustment button 110, 110′ which is used for resettingthe local atmospheric pressure for the altimeter function present instandby data display mode. Various additional buttons, pushbuttons orswitches, may be used, linked with the information displayed by thesoftware on the screen, to perform various functions similar to those ofthe integrated electronics standby instruments of the prior art (placingmax or min speed marks for example) or to those of the automatic pilotcontrol panels of the prior art (selecting engagement or disengagementof the automatic pilot, selecting the automatic pilot mode, etc.). Forthe pilot, the functions of these buttons are defined by software indirect relation with the indications displayed on the screen, so thatthe same buttons may be used for a number of different functionalities,including functionalities belonging to the two different modes of theequipment.

The set point adjustment control buttons are in any case active (that isto say that they are executing a set point adjustment) only on theequipment that is in the piloting set point display mode. On the otheritem of equipment, they are inactive, that is to say that rotating themdoes not change the piloting set points. They may however be active foranother function linked to the standby data display, but this is notusually desirable for reasons of safety.

Thus, in the example described, preference has been given to providingon the equipment a specific button 110, 110′ for resetting atmosphericpressure, even though in theory one of the set point adjustment buttons103 to 109 could be used for this reset since these buttons define noset point when the equipment is in standby data display mode. Thespecific button 110, 110′ is not active for carrying out an atmosphericpressure reset unless the equipment is in standby data display mode.

In the case of commercial passenger transport airplanes, thanks to theinvention, the automatic pilot safety requirements are satisfied (10⁻⁶failures per hour, a rate obtained thanks to redundancy) and those ofthe standby functions (10⁻³ failures per hour), with a simplifiedinstrument panel architecture.

1. An aircraft instrument panel, comprising a main display system forhorizon and necessary piloting parameters, and on the other hand an itemof automatic pilot control equipment, which comprises manual pilotingset point control buttons and finally an item of standby displayequipment allowing the display, independently of the main displaysystem, of integrated standby data including a standby horizon, whereinthe automatic pilot control equipment and the standby display equipmentare two identical items of equipment from the hardware point of view andthe software point of view and each comprises a display screen capableof displaying the integrated standby data, and in that the two items ofequipment have at least two operating modes, one of the modes being anintegrated standby data display mode and the other being a mode ofdisplaying the automatic pilot set points given by the pilot, the itemsof equipment each operating in a different mode in normal operatingconditions.
 2. The instrument panel as claimed in claim 1, wherein theset point control buttons are active on the equipment that is inpiloting set point display mode and inactive as control buttons for setpoint adjustment on the equipment that is in standby data display mode.3. The instrument panel as claimed in claim 1 wherein the controlbuttons of the item of equipment that is in piloting set point displaymode allow the establishment of set point adjustment signals that arealso transmitted to the other item of equipment, which also processesthese signals without however displaying the set points.
 4. Theinstrument panel as claimed in claim 1, wherein each of the two items ofequipment comprises a switchover control button which is used to invertthe operating modes of the two items of equipment.
 5. The instrumentpanel as claimed in claim 1, wherein means are provided, in the event ofthe failure of one of the two items of equipment, for switching theother item of equipment to automatic pilot set point display mode if itis not already in that mode.
 6. The instrument panel as claimed in claim1, wherein the items of equipment comprise a control button distinctfrom the piloting set point adjustment buttons, for resetting theatmospheric pressure for the purpose of an altitude computation, thisbutton being active for the resetting of pressure only when theequipment is in standby data display mode.
 7. An integrated item ofstandby equipment intended to be mounted on an instrument panel asclaimed in one of the preceding claims, wherein it comprising both thehardware and software capable of displaying on a single display screeneither standby data, including a standby horizon, when the equipment isoperating in a standby data display mode, or automatic pilot set pointswhen the equipment is operating in a piloting set point display mode,the equipment being provided with piloting set point adjustment buttons.8. The equipment as claimed in claim 7, wherein it comprising anatmospheric pressure reset button, active when the equipment is instandby data display mode.
 9. The equipment as claimed in claim 8,wherein the equipment has a mode switchover button, active for invertingthe equipment operating mode and capable of sending a mode inversionsignal to another identical item of equipment of the same instrumentpanel.
 10. The instrument panel as claimed in claim 2, wherein thecontrol buttons of the item of equipment that is in piloting set pointdisplay mode allow the establishment of set point adjustment signalsthat are also transmitted to the other item of equipment, which alsoprocesses these signals without however displaying the set points. 11.The instrument panel as claimed in claim 2, wherein each of the twoitems of equipment comprises a switchover control button which is usedto invert the operating modes of the two items of equipment.
 12. Theinstrument panel as claimed in claim 3, wherein each of the two items ofequipment comprises a switchover control button which is used to invertthe operating modes of the two items of equipment.
 13. The instrumentpanel as claimed in claim 2, wherein means are provided, in the event ofthe failure of one of the two items of equipment, for switching theother item of equipment to automatic pilot set point display mode if itis not already in that mode.
 14. The instrument panel as claimed inclaim 3, wherein means are provided, in the event of the failure of oneof the two items of equipment, for switching the other item of equipmentto automatic pilot set point display mode if it is not already in thatmode.
 15. The instrument panel as claimed in claim 4, wherein means areprovided, in the event of the failure of one of the two items ofequipment, for switching the other item of equipment to automatic pilotset point display mode if it is not already in that mode.
 16. Theinstrument panel as claimed in claim 2, wherein the items of equipmentcomprise a control button distinct from the piloting set pointadjustment buttons, for resetting the atmospheric pressure for thepurpose of an altitude computation, this button being active for theresetting of pressure only when the equipment is in standby data displaymode.
 17. The instrument panel as claimed in claim 3, wherein the itemsof equipment comprise a control button distinct from the piloting setpoint adjustment buttons, for resetting the atmospheric pressure for thepurpose of an altitude computation, this button being active for theresetting of pressure only when the equipment is in standby data displaymode.
 18. The instrument panel as claimed in claim 4, wherein the itemsof equipment comprise a control button distinct from the piloting setpoint adjustment buttons, for resetting the atmospheric pressure for thepurpose of an altitude computation, this button being active for theresetting of pressure only when the equipment is in standby data displaymode.
 19. The instrument panel as claimed in claim 5, wherein the itemsof equipment comprise a control button distinct from the piloting setpoint adjustment buttons, for resetting the atmospheric pressure for thepurpose of an altitude computation, this button being active for theresetting of pressure only when the equipment is in standby data displaymode.